Importer Flow Control

Flow control defines how document handling branches and sequences inside importer pipelines.

Use flow control when you need conditional behavior such as:

• route a document to different handlers based on metadata or content
• apply one handler chain when a condition matches and another when it does not
• combine multiple conditions for advanced branching
• reject documents meeting a condition

Where It Applies

Flow control is specific to Importer configuration.

Start with these related types:

• ImporterConfig
• If
• IfNot
• Condition
• AllOf
• AnyOf
• NoneOf
• Reject

Typical Pattern

A common pattern is:

1. define a condition that inspects one or more fields
2. branch into then and else handler blocks
3. continue normal importer processing

Configuration Shape

handlers is a list, and every entry in it is an object with a single key:

Key	Value
handler	An ordinary handler — a parser, transformer, splitter, or Reject
if	A condition plus a then list and an optional else list
ifNot	The same, with the condition inverted

then and else are lists of those same entries, so branches nest as deeply as needed. In XML the entries become elements of the same names — <handler>, <if>, <ifNot> — inside <handlers>.

A condition is either a single condition identified by its class, or one of the allOf / anyOf / noneOf groupings, each holding a list of conditions.

Example

Documents created between ten years and one year ago are split as CSV; everything else is dropped from the crawl.

{
  "handlers": [
    {
      "if": {
        "condition": {
          "class": "DateCondition",
          "fieldMatcher": {
            "pattern": "date_created"
          },
          "valueMatcher": {
            "operator": "ge",
            "date": "NOW-10Y"
          },
          "valueMatcherRangeEnd": {
            "operator": "lt",
            "date": "NOW-1Y"
          }
        },
        "then": [
          {
            "handler": {
              "class": "CsvSplitter",
              "separatorCharacter": ",",
              "referenceColumn": "id"
            }
          }
        ],
        "else": [
          {
            "handler": {
              "class": "Reject",
              "message": "Outside the retention window"
            }
          }
        ]
      }
    }
  ]
}

The same configuration in XML:

<handlers>
  <if>
    <condition class="DateCondition">
      <fieldMatcher>date_created</fieldMatcher>
      <valueMatcher operator="ge" date="NOW-10Y"/>
      <valueMatcherRangeEnd operator="lt" date="NOW-1Y"/>
    </condition>
    <then>
      <handler class="CsvSplitter" separatorCharacter="," referenceColumn="id"/>
    </then>
    <else>
      <handler class="Reject" message="Outside the retention window"/>
    </else>
  </if>
</handlers>

Combining Conditions

allOf, anyOf and noneOf each take a list of conditions in place of a single one. Here a document is dropped only when it is both a PDF and untitled:

{
  "handlers": [
    {
      "if": {
        "condition": {
          "allOf": [
            {
              "class": "TextCondition",
              "fieldMatcher": { "pattern": "Content-Type" },
              "valueMatcher": { "pattern": "application/pdf" }
            },
            {
              "class": "BlankCondition",
              "fieldMatcher": { "pattern": "title" }
            }
          ]
        },
        "then": [
          {
            "handler": {
              "class": "Reject",
              "message": "Untitled PDF"
            }
          }
        ]
      }
    }
  ]
}

In XML the group wraps repeated <condition> elements:

<handlers>
  <if>
    <condition>
      <allOf>
        <condition class="TextCondition">
          <fieldMatcher pattern="Content-Type"/>
          <valueMatcher pattern="application/pdf"/>
        </condition>
        <condition class="BlankCondition">
          <fieldMatcher pattern="title"/>
        </condition>
      </allOf>
    </condition>
    <then>
      <handler class="Reject" message="Untitled PDF"/>
    </then>
  </if>
</handlers>

Groups nest, and so does if itself — an if inside a then or else list is often clearer than a deeply nested group.